Some Deerhounds have a problem with liver disease and/or a blood clot (thrombus; plural, thrombi) in the vein that carries blood from other abdominal organs to the liver, called the portal vein. A clot in the portal vein is like construction on a highway—it slows or even completely stops traffic (blood) from flowing into the liver. As a result, blood backs up behind the clot, not only in the portal vein itself, but also in the veins that feed into the portal vein from the stomach and spleen (gastrosplenic vein) and intestines (mesenteric veins). This can have several consequences:
- Because blood is more likely to clot if it slows or stops flowing, thrombi sometimes form in the feeder veins as well as the portal vein.
- The liver no longer receives its usual blood supply, leading to chronic injury and eventual liver failure.
- Blood pressure increases behind the portal vein thrombus, leading to the development of “acquired” portosystemic shunts that allow blood to bypass the liver entirely. The liver normally removes various toxic substances from the blood before the blood reaches the rest of the body. When blood bypasses the liver, the toxins can make the dog sick.
We are doing research into this problem, but this is what we know so far:
Dogs with this problem often develop an atrophied liver, thrombi in the veins leading to the liver and/or spleen, or both. The liver appears to atrophy over time—it can look normal for years. Thrombi can dissolve, but many remain in place, and scar tissue can form, making them impossible to dissolve. And, as mentioned, thrombi in the portal vein can lead to the development of acquired shunts to get blood past the blockage.
There is much still unknown about liver disease and portal vein thrombosis (PVT) in dogs. By the time a dog is discovered to have these problems, it often is unclear which came first. Did underlying liver disease lead to thrombosis, or did portal vein thrombosis result in chronic liver disease?
Presentation of This Disease (or diseases)
We’re not yet sure whether we are dealing with one or two diseases, as some dogs have both the liver problem and thrombi (portal vein thrombosis and/or splenic thrombosis), while others only apparently have one or the other. Our research project will help us understand whether or not this is really the case.
Symptoms
Here are some of the symptoms owners have seen with their affected dogs:
No symptoms: Dogs can be asymptomatic, and this problem has been diagnosed incidentally.
Be “off” – some dogs have just not been right with no specific symptoms.
Intolerance of drugs metabolized by the liver: Some dogs, if given drugs that are metabolized by the liver, can get sick (a couple have had this reaction to doxycycline) or just seem “off.” Some dogs’ liver values get significantly worse when they are on one of these drugs. One dog, when given several of these drugs at once, developed jaundice.
Digestive Upset: Dogs with this condition have had vomiting; inappetence; bright yellow, orange, and/or bloody stool; and other digestive problems.
A couple of dogs have had urinary symptoms.
Idiopathic Renal Hematuria: One dog had visible blood in the urine (diagnosed as bilateral Idiopathic Renal Hematuria) that improved as the liver improved. It is unknown whether or not the renal hematuria was related to the liver/thrombus problem.
Volvulus: Two dogs have presented with volvulus (one small intestine, one spleen), and thrombi were discovered. It is unclear whether the volvuli were related to the liver/thrombus problem or not.
Neurological symptoms: In later stages, dogs can exhibit hepatic encephalopathy and other neurological signs of advanced liver disease. Liver values are not necessarily very high when this happens.
Perforated intestine: A couple of dogs have presented with a perforated intestine, which vets assume is a foreign body but instead is caused by a PVT cutting off the blood supply to the small intestine. These dogs can go into DIC (Disseminated Intravascular Coagulation).
Death: Some dogs show no sign of this problem until they develop sudden severe symptoms and die or need to be euthanized.
Age of onset of symptoms has been documented in dogs as young as 3 years and as old as 10 years of age.
Diagnostics that have indicated a problem in affected dogs:
Abnormal blood test results: While tests that indicate liver injury can be higher than normal, they often aren’t alarmingly high, even on very sick dogs. These include higher serum ALT and AST activities, higher serum alkaline phosphatase activity, higher serum bilirubin concentration, and lower serum BUN and albumin concentrations.
Atrophied liver: in later stages, the liver looks small on ultrasound.
Thrombi: PVT, often with acquired shunts, or splenic thrombi can usually be seen on ultrasound when they are present.
Urate crystals/stones: Urate crystals and/or stones (which typically indicate a liver problem) have been found.
Treatment
So far, there has been only one dog that has had a liver biopsy. Although it is hard to generalize from one dog, for what it’s worth, this dog was prescribed the following by the internal medicine specialist treating her:
For the liver:
- Denamarin
- Vitamin E
- Ursodiol
To prevent the clot from growing:
- Low-dose aspirin
Probiotic
She was also prescribed AmoxiClav and Enrofloxacin for another problem that may also be helping her liver.
She was given Sucralfate to help with vomiting, and, moving forward, omeprazole might need to be given if digestive symptoms return.
With treatment, this dog’s bloodwork returned to normal, and the dog was asymptomatic and felt good for more than a year after starting this regimen until she developed symptoms of liver failure and was euthanized. However, this is just one dog, so, assuming other Deerhounds have the same condition, it is unclear whether this regimen will work with other cases.
Help the Study!
We are just beginning to learn about this condition, so the more information we can gather, the better. If your dog has been diagnosed with a liver problem and/or a thrombus, we want to hear from you! Please contact us to tell us about your experience.
Congenital Liver Shunt: We would also like to hear from breeders and owners of puppies with a congenital liver shunt. We don’t know whether or not the adult-onset liver disease described above is related to the congenital portosystemic shunts (PSS, also called liver shunts) that have been seen in Deerhound puppies for decades. Therefore, we are also soliciting liver samples from liver shunt puppies to see whether there are any similarities.
We are also still collecting biopsy and necropsy reports and, if possible, tissue samples, from both affected and normal dogs, as well as dogs with a congenital liver shunt—we are paying people up to $150 to send us tissue samples when their dog passes on.